Controlled compression winding method and apparatus

Abstract

A method and apparatus for forming rolls of compressible materials such as a mineral wool felt, wherein the felt is rolled up in a space defined by a pair of conveyors and a compression roll. The position of at least one of these elements, particularly the compression roll, is varied during the course of winding, according to a preset program and as a function of the length of felt already rolled, in such a way as to produce a predetermined thickness in each turn of the rolled felt, whereby it is possible to achieve particularly more uniform compression over the entire length of the rolled up felt strip.

What is claimed as new and desired to be secured by letters patent of the United States is: 
     
       1. A method of forming rolls from strips of compressible material, comprising: continuously transporting the strip of material into a restricted space defined by at least three elements driven with a movement which causes the strip to be rolled onto itself;   successively contacting the strip with each of these element such that rolling up of said strip occurs;   varying a position of one of the elements to direct the rolling process during the successively contacting step;   controlling the position varying step in accordance with a predetermined program as a function of the length of the strip rolled up, in such a way as to produce a predetermined thickness, which may vary during the course of the rolling up of said strip according to a predetermined algorithm, whereby said strip is uniformly compressed over a predetermined length of said strip.   
     
     
       2. A method according to claim 1, wherein the controlling step comprises: using the initial thickness of the strip to be rolled as a parameter in said predetermined program.   
     
     
       3. A method according to claim 1, wherein said controlling step comprises: selecting an algorithm which produces at most an equal thickness in the turns or a thickness which slightly decreases from the commencement to the completion of the rolling process.   
     
     
       4. A method according to claim 2, wherein said controlling step comprises: selecting an algorithm which produces at most an equal thickness in the turns or a thickness which slightly decreases from the commencement to the completion of the rolling process.   
     
     
       5. An apparatus for forming rolls for strips of compressible material, comprising: an assembly of at least three elements defining a space in which said strip is subjected to a rolling process wherein said strip is rolled up into a roll;   means for driving said elements such that upon contact therewith, the strip is adapted to be rolled onto itself within the space defined by said elements, at least one element being movable in relation to the others during the course of the operation;   motor means for displacing said movable element;   control means for controlling said motor means;   plural sensors for monitoring the formation of said roll; and   computing means having a memory and operative according to a predetermined program stored in said memory for processing measurement signals produced by said sensors to derive thickness signals applied to said control means to control the thickness of said strip during rolling as a function of the length of the strip rolled up so as to produce a predetermined thickness which may vary according to a predetermined algorithm whereby said strip is uniformly compressed over the length of said strip.   
     
     
       6. An apparatus according to claim 5, wherein said at least three elements defining the space in which the rolling process takes place comprise: a first conveyor on which a belt is transported as far as said space;   a second conveyor disposed at an end of and apart from the first conveyor and forming an acute angle with said first conveyor;   a compression roller situated in the acute angle defined by the first and second conveyors, said compression roller constituting the element which is displaced during the course of the rolling process.   
     
     
       7. An apparatus according to claim 6, wherein said motor means comprises: an arm supporting said compression roller; and   hydraulic jack means for producing a displacement in said arm.   
     
     
       8. An apparatus according to claim 7, comprising: a position coder rigid with the arm supporting the compression roller for transmitting to the computing means signals indicative of the position of said arm, which signals constitute one of the parameters employed in deriving said thickness signals to determine the operation of the motor means.   
     
     
       9. An apparatus according to one of claim 8, wherein said sensors comprise: means for detecting a length of the felt already rolled up, whereby the commencement of introduction of the strip into the space in which rolling takes place is established; and   means for measuring the time after commencement of introduction of the strip and the speed of travel of the strip.   
     
     
       10. An apparatus according to claim 9, wherein said computing means processes the angular displacement of the arm during the course of roll forming and to that end is programmed so that the angle A of the arm with a vertical axis satisfies the relationship: ##EQU4## in which the symbols employed are respectively: R: radius of the roll already formed. r: radius of the compression roller.   L: length of the arm between the axis of rotation and of the compression roll,   a: H+h-R,   b: R cotg α/2-D,   γ: arc tan r/L,   H+h: distance from the axis of rotation to a belt of the first conveyor,   D: distance separating the point of convergence of the direction of the faces of the first and second conveyors and the projection of the center of rotation of the arm on the face of the first conveyor, and   α: acute angle formed between the first and second conveyors.